The formation mechanism of zeolite-templated carbons (ZTCs) is investigated. The carbon uptake into zeolite nanochannels during chemical vapor deposition (CVD) is found to proceed in the following three stages: (i) initial rapid carbon uptake from zeolite-particle surface to its center, (ii) gradual increase of carbon density at a constant rate, and (iii) termination of carbon deposition. The molecular-level structure evolution is also analyzed in detail. By CVD, curved nanographenes are formed inside the nanochannels of zeolite, and they are not perfectly connected each other. The subsequent heat treatment (>800 °C) coalesces the nanographenes to form a continuous 3D framework, and at the same time, a significant number of dangling bonds (non-terminated edge sites) are formed that are protected from air by the zeolite so that they are stable at room temperature. However on template removal, the dangling bonds react with ambient H₂O or O₂ and are terminated by oxygen-functional groups or H. The dangling bonds in the carbon/zeolite composite can also be terminated by H when the composite is subjected to a H₂ treatment at 700 °C. In this case, the number of dangling bonds in the carbon/zeolite composite is decreased, and the addition of oxygen-functional groups when the template is removed becomes less significant.

This study has focused on the recycling of carbon fiber-reinforced thermoplastics (CFRTP) based on polyethersulfone (PES) that have a high thermal stability from the viewpoint of reusing the carbon fibers (CFs). The first recycling method is the remolding of the CFRTP; i.e., the reuse of CFs through material reuse. From the viewpoint of collection, it is expected that the waste CFRTP is gathered in a shredded form. Therefore, shredded prepregs that simulate waste CFRTP were prepared, and discontinuous CFRTP was molded as reshaped CFRTP. The reshaped CFRTP had isotropic mechanical properties; the bending modulus and strength were 35 GPa and 400 MPa, respectively. The other recycling method is the reuse of the CFs. The matrix resin was removed by pyrolysis and chemical decomposition, and the CFs were recovered by a pyrolysis process (Re-pyro-CF) or a chemical process (Re-chem-CF). It is difficult to perfectly thermally decompose PES and it is also difficult to obtain clean surfaces of Re-pyro-CF. As the result under the optimum conditions in our work the fiber tensile strength decreased by 50% compared with fresh CF (Fre-CF). Meanwhile, Re-chem-CF depolymerized under ambient pressure using N,N-dimethylformamide could be recovered with a clean surface and its tensile strength was about the same as that of Fre-CF.

The durability of MgO-templated mesoporous carbons as electrode materials for electric double layer capacitors was investigated at 3.0 and 3.2 V in propylene carbonate based electrolytes. Their capacitance retention was comparable to or slightly worse than that of microporous activated carbons at low current densities. On the other hand, at high current densities, the mesoporous carbons showed better stability than the microporous ones. Despite pore filling and the accumulation of products in the mesopores, numerous mesopores for the fast migration of ions were retained after the durability test. Regardless of the porosity of the electrode materials, pore filling was more significant on the negative electrode than on the positive electrode; therefore, capacitance degradation was dominated by the capacitance loss of the negative electrode.

An amorphous Fe(III) oxide material, which is naturally produced by an aquatic bacterium, Leptothrix ochracea, has a tubular morphology with a diameter of ca. 1 µm. We used thesee iron oxide tubes as a template to produce a novel porous carbon and a humidity sensor. Furfuryl alcohol or resorcinol-formaldehyde resin mixed with iron oxide was polymerized and carbonized. After treatment with hydrochloric acid followed by hydrofluoric acid, the samples retained the tubular shape and showed high BET surface areas in the range 220∼1260 m² g⁻¹. The surface of the iron oxide tubes can be coated by carbon layer using CVD with a 20 vol% C₂H₂/Ar gas at 400 °C. The electrical resistance of the carbon-coated iron oxide tube (C/BIOX) was measured. Since the resistance depended on the humidity of the atmosphere at room temperature, C/BIOX may be used as an extremely small humidity sensor.

Porous carbons have the potential to be an ideal template for various materials, because of their simple geometry and various shapes. We synthesized BaTiO₃ nanocrystals in the internal nanopores of carbon nanohorns by sol-gel methods. Direct synthesis of BaTiO₃ in carbon nanohorns produced 2∼4 nm diameter spherical particles, although a typical sol-gel technique for nanoceramic synthesis produces spherical crystals with a diameter of the order of 10 nm. The BaTiO₃ nanoceramics were composed of only a few crystal unit cells, and can be considered zero-dimensional BaTiO₃ nanoceramics. BaTiO₃ nanoceramics synthesized by TiO₂ synthesis in carbon nanohorns and subsequent insertion of barium diethoxide were one-dimensional structures with a high aspect ratio (2∼4 nm in diameter and 40∼60 nm in length). Those nano-spherical and rod-like BaTiO₃ nanoceramics are required in nanotechnology for their unique dielectric and piezoelectric properties.

Graphene oxide (GO) is generally used as a graphene precursor. The reduction of GO occurs by chemical reaction with a reducing agent, and a physical stimulus such as light, heat and pressure. GO is highly reducible, that is, it is an oxidizing agent. It is known that GO works as an oxidizing agent for alcohols. On the other hand, there are reports that GO works as an oxidation catalyst for alcohols. Reactants and catalysts are completely different, and must never be confused. The difference between GO analogues with respect to their roles as a reactant and a catalyst is discussed based on structural analysis before and after the reaction, and a study of reaction intermediates.

The weight loss rate of vapor grown carbon fibers (VGCF) was investigated in a KOH aqueous solution during steady-state polarization measurements in the potential range 0.45 to 0.75 V against a Hg|HgO reference electrode. In particular, we measured the amount of oxygen produced by a dissolved oxygen gas sensor and used the results to calculate the weight loss rate (ΔW) of VGCF by the carbon oxidation reaction (COR). When the concentration of KOH was 0.1 M, the ΔW is almost same as that reported in a previous report. In addition, a decrease in the onset potential of COR as well as a significant increase in the ΔW was found when the concentration of KOH was increased to 1.0 M.

Temperature-programmed desorption measurements are very useful in an evaluation of the carbonization/graphitization of carbon precursors and the reduction of transition metal species. Here, the catalytic carbonization/graphitization behaviors of furfuryl alcohol polymer in the pores of Ni- or Co-loaded MCM-48 mesoporous silica was investigated. CH₄ can reduce Ni(II) to Ni(0) at 600 °C, and the metallic Ni can then act as a catalyst for the formation of a graphitic structure within the mesopores at 1000 °C. Co(II) species can be reduced by CO at 400 °C, and the metallic Co acts as a catalyst for Boudouard reaction, steam reforming and dry reforming of CH₄, and partial graphitization up to 900 °C.